Here is the correct pinout for a Pro Micro. I used that to end up with the same
MATRIX_COL_PINS as you
Here is a link to my QMK config for the 30wer. This can be cloned and compiled directly. I plan to submit a pull request to QMK as soon as I finish up the readme.
My default keymap uses
LT(1, KC_SPC) (on the lower right key) to change layers, and it’s working pretty well for me. This way you get a space if you press the key, and layer 1 if you hold it. Other than that it’s pretty basic, for now.